In the automotive industry, the tires used on cars and light trucks are getting larger and heavier, creating a problem for the technicians installing them. Employers and employees are concerned about back injuries and other muscle strains. As of now there are no specific tools for the installation of tires for the automotive industry. Many different styles of tire lifts have been designed, sold and patented for the heavy truck industry. Most of these tools are unsuitable for use in the automotive industry due to their design. These tools are designed to lift tires and tire assemblies from 250 lbs to 1000 lbs. These tools are of heavy construction and have limited height capabilities to a (maximum of 14 inches), making them awkward to use. In the automotive industry speed and mobility are required and the ability to raise the tire to chest height is necessary.
One of the other drawbacks to current heavy tire lift design is the means which the tire is lifted: either hydraulically pumped cylinder or by cable crank means. Each of these methods is very slow and time consuming and generally not considered worthwhile for smaller automotive tires.
Examples of prior art, heavy tire lifts which have been either designed, patented or sold by various manufactures include U.S. Pat. Nos. 6,382,644 (Rawlings); 5,562,389 (Mitchell); 5,112,070 (Hahn); D473,692 (Tafoya); 6,095,745 (Garnett); and 6,106,214 (Saffelle et al). None of the tools described in the noted prior art patents are suitably arranged for quickly lifting and lowering vehicle wheels thereon with a simple and low cost device.
U.S. Pat. Nos. 6,382,644 to Rawlings and 6,106,214 to Saffelle describe further examples of lift devices for wheels. Either a complex jack or hydraulic actuator is required for lifting the wheels thereon in a slow and time consuming operation.
Another known type of lift for vehicle wheels is available by Rotary™, a Dover™ company of Madison, Ind., USA. The lift comprises a wheeled base including an upright fixed thereon upon which a wheel support carriage is slidably mounted. An electric battery powered motor is provided for lifting the wheel relative to the base. Such a motor is particularly slow and provides a limited number of lifting cycles before charging is required. Recharging time thus limits continuous use of the lifting device.
The lifting device by Rotary™ is limited in its use according to several aspects. The most prohibitive is the tall mast which will hit the fenders of most vehicles when the tool is pushed into the wheel well to install a tire. The second are the small wheels and casters the tool sits on, which make the tool hard to use in a shop environment. Thirdly, the device is limited to a 110 lbs capacity due to the electric motors used. Commonly available 19.5 inch diameter wheels rims with tires often weigh 130 lbs and accordingly the lifting device available by Rotary™ could not raise many wheels used on one and two ton vehicles.
U.S. Pat. No. 5,184,930 to Kuhn describes a vehicle lifting system in which a pair of lifting jacks are required to be mounted on opposing sides of a vehicle for actuation by a common actuator located remotely from the two lifting jacks. The lifting jacks are required to be used in pairs and are intended for heavy lifting in a controlled manner contrary to the independence and agility desired in a lifting device for lifting a vehicle wheel, for example in an automotive servicing location and the like.